The quantum information technology is one of front and significant research directions in the physics field, and implementing quantum calculation and quantum communication based on a single photon state manipulation is the most important physic implementing method of the current quantum information technology. However, an ideal single photon emission device lacks at present. Thus, for now, experiment demonstrations of the quantum key communication all simulate a single photon emission by attenuated laser light source, but such experiments need a extremely complicated optical system, and a generation efficiency of a single photon is very low, it is impossible to eliminate existence of multiple-photon, and a possibility of being attacked by the multiple-photon cannot be avoided. This will bring a security risk to the quantum communication, for example, an eavesdropper may eavesdrop through a Photon-Number-Splitting (PNS) method. Thus, how to obtain a stable, highly effective and reliable single photon source has become a bottleneck problem in applications of the quantum communication and a quantum cryptography.
A semiconductor quantum dot structure will be encountered with a very strong three dimensional quantum confinement effect since sizes thereof in X, Y and Z directions are between a few nanometers and a few tens of nanometers, energy level distributions thereof presents a shape of a hydrogen-like spectrum, and it has a typical “atom-like” structure; moreover, the semiconductor quantum dot structure further has advantages such as a large tunable wavelength range, easy integration, and the like, and thus, it becomes one of ideal choices for manufacturing a single photon emission device.
However, it is very difficult to grow a quantum dot structure of which a density, a size and a position can be controlled by using a quantum dot growth process in a traditional Stranski-Krastanow mode (which is called an SK mode for short). In order to solve this problem, recently adopting a technology of epitaxially growing a quantum dot structure on a nano-patterned substrate is widely focused, but these methods not only have tedious processes, but also have larger damages on the substrate, which is not benefit to obtain a quantum dot structure with a high quality.